The present invention relates generally to devices, systems and methods of determining the location of mobile personnel and, particularly, to devices, systems and methods of determining the location of personnel working under hazardous conditions outdoors and/or within one or more structures.
Firefighters, first responders, and military personnel work in the world's most dangerous occupations in some of the world's most hazardous environments. Firefighters can easily become disoriented or separated since most firefighting is done in zero visibility as a result of smoke. First responders constantly place themselves in danger, which sometimes results in becoming trapped or disabled. Military personnel face dangerous conditions on a daily basis, and knowing where each soldier is located, whether performing routine tasks or under hostile fire, would be extremely valuable to the commanding officer. In all cases, there are examples where fatalities might have been prevented or injuries lessened in severity with a location system that provides location information about a person in need of assistance to other personnel to relatively quickly find that person.
In cases in which personnel are outdoors, global positioning system (GPS) devices and solutions can, for example, be used to roughly locate such personnel. However, multipath propagation problems lead to poor signals and inaccurate results with GPS devices when used within a structure. Moreover, without significant processing, GPS devices are typically accurate to approximately ±3 m. Although such inaccuracy can be acceptable for locating personnel and objects outdoors, an inaccuracy of 3 m within a structure can, for example, result in sending a rescue team to a wrong floor within the structure and thus squandering precious time in a rescue mission. Like GPS devices, other localization devices which use, for example, radio frequency energy, ultrasound energy and/or infrared energy can suffer from multipath propagation problems, leading to substantial inaccuracy when used within structures.
It thus remains desirable to develop improved devices, systems and methods of determining the location of mobile personnel that reduce the severity of or eliminate the above-described and other problems with current location devices, systems and methods.